The Landless are a semi-nomadic human sub-society, usually traveling with one or two dogs. They move from place to place, living in rented or borrow space. Finding temporary work and moving on once the contract is done.
The two-generation family is the central unit of their society. Every time an offspring gets married, she or he splinters off from her or his family to form their own.
Once all the children have moved on, the parents join other orphaned parents to travel and seek work together.
Once a group of orphaned parents has reached a certain critical point, they stop traveling, build a house and stay put until their death.
These retirement houses are usually very self-sufficient, considering the concentration of skills, especially at first, but outside input is invaluable. So, families come from time to time to contribute.